The proposed research intends to investigate the therapeutic potential of custom software operating on a hand held portable digital device to induce and maintain changes in eating behavior. Specific aims of this effort include enhancement of the software, and extending to additional platforms. A clinic server (base station) will be developed. Two clinical trials are proposed: one a controlled trial comparing the digital system to standard interventions known to be effective in aiding the maintenance of weight loss in obese subjects. The second trial tests the software in a nationwide sample of internet users, focusing on its potential as a self-help tool for aiding diet change. A successful research effort would be expected to produce a valuable tool to combat obesity and other serious disorders where diet change is a critical aspect of care. PROPOSED COMMERCIAL APPLICATION: The research will produce an adjunctive treatment system for targeted diet change. The commercial application of this technology will extend to professional and self-help systems, and specialized tools for health care professionals. The population of individuals with weight and metabolic disorders in the U.S. is large, thus a successful effort will create a product with substantial potential.